CN107408899B

CN107408899B - Variable speed power generation electric device and variable speed power generation electric system

Info

Publication number: CN107408899B
Application number: CN201680012006.8A
Authority: CN
Inventors: 阪东明; 名仓理
Original assignee: Hitachi Mitsubishi Hydro Corp
Current assignee: Hitachi Mitsubishi Hydro Corp
Priority date: 2015-02-25
Filing date: 2016-02-22
Publication date: 2020-05-12
Anticipated expiration: 2036-02-22
Also published as: CN110266243B; JP6243083B2; ES2927210T3; CN110266243A; US10784808B2; US20180034399A1; EP3576282A1; EP3264583A4; JPWO2016136682A1; EP3264583A1; WO2016136682A1; EP3576282B1; CN107408899A; EP3264583B1; US20200144949A1; ES2772831T3; US10536104B2

Abstract

In a variable speed power generation electric device, a power converter includes 6 2-terminal arms in which k unit converters capable of outputting an arbitrary voltage are connected in series, an AC rotary electric machine includes 2-layer coils and an armature winding having a 60-degree phase band, the armature winding is divided into a first pole side and a second pole side, a neutral point is led out as a two-way star connection through 2 sets of 3-phase terminals, a 3-phase terminal on the first pole side is connected to a first terminal of 3 arms of the power converter, a second terminal of the 3 2-terminal arms is star-connected to a first terminal of a DC power supply, a 3-phase terminal on the second pole side of the armature winding is connected to a second terminal of the remaining 3 2-terminal arms of the power converter, a first terminal of the 3 2-terminal arms is star-connected to a second terminal of the DC power supply, the DC current of the DC power supply is 3-divided into 3 parts, and the 3 2-terminal arms connected to the second terminal of the DC power supply are sequentially passed through, Armature winding, 3 terminal arms of 2 that are connected with the first terminal of direct current power supply.

Description

Variable speed power generation electric device and variable speed power generation electric system

Technical Field

The present invention relates to a variable-speed generator/motor system in which a modular multilevel PWM power converter (hereinafter, referred to as an "MMC converter") and an ac rotary electric machine are connected, and a variable-speed generator/motor system using the variable-speed generator/motor system.

Background

The circuit of the MMC converter is composed of a unit converter that generates a desired voltage by controlling a modulation rate of a PWM converter having a voltage source of an energy storage element of a voltage source characteristic such as a capacitor, a secondary battery, or the like. The voltage of the energy storage element of the unit converter fluctuates according to charging and discharging of a cycle determined by the ac frequency. The unit converters are connected in series to form a 2-terminal arm, a first terminal of the arm is connected to each phase terminal of the ac power supply, and a second terminal of the arm, which is star-connected, is connected to a terminal of the dc power supply.

According to this configuration, the arms connected to each other generate a desired ac frequency voltage to control ac current, and superimpose dc current to convert power with the dc power supply.

The control of the MMC converter includes a current control (hereinafter, referred to as "converter current control") for adjusting the arm current in accordance with an ac current command and a dc current command from the outside, a function (hereinafter, referred to as "inter-stage control") for balancing the average voltage of the energy storage elements among the unit converters by mutually adjusting the modulation factor of the PWM converters provided in the unit converters in the arm, and a function (hereinafter, referred to as "inter-phase balance control") for balancing the total energy stored in the energy storage elements in the arm among the arms. The implementation of this interphase balance control requires a circuit element for suppressing the inter-arm circulation current.

Patent document 1 discloses a method of providing a circulation current suppression reactor between the first terminal of each phase arm and the ac power supply terminal (hereinafter, referred to as "DSMMC converter" in the present invention).

Patent document 2 discloses a method of providing a transformer having secondary and tertiary windings connected in a two-way star configuration, and canceling out dc magnetomotive force of a transformer core caused by a circulating current while using leakage reactance of the secondary and tertiary windings as a current suppressing circuit element (hereinafter, referred to as "DIMMC converter" in the present invention).

Patent document 3 discloses a method of providing a transformer having second and third windings that are zigzag-connected, and canceling a dc magnetomotive force of a transformer core caused by a circulating current by using leakage reactance of the second and third windings as a current suppressing circuit element (hereinafter, referred to as a "zcmc converter" in the present invention).

Non-patent document 1 discloses a method of connecting the dc terminals of 2 DSMMC converters behind each other as a variable-speed power source, connecting one ac terminal to an ac system, and connecting the other ac terminal to an ac rotating electrical machine to realize a variable-speed power generation electric device.

According to this method, even if connected to the MMC converter, a direct current is not superimposed on the alternating-current rotary electric machine. Therefore, the present invention is suitable for use in a case where an ac rotary electric machine directly connected to an ac system and operating at a fixed frequency is variable in speed.

Patent document 4 discloses a method of connecting a zcmcmc converter to an ac rotary electric machine. It is claimed that an alternating current electric system can be realized by this method even without providing a circulation current suppressing reactor.

Patent document 5 discloses a vector measurement method of variable frequency voltage and current signals of an ac rotary electric machine.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 5189105

Patent document 2: international publication No. 2009/135523

Patent document 3: japanese patent No. 5268739

Patent document 4: japanese patent laid-open publication No. 2013-162735

Patent document 5: japanese patent No. 5537095

Non-patent document

Non-patent document 1: securinega , west village and jing, red city thai, "" モジュラー, マルチレベル PWM インバータを with いた high voltage モータドライブ: experiment '

at

1 , 400V, 15 kW ミニモデルによる in experiments, the society of learning culture 35468D, 4 months in 2010, 130 coil, No. 4, pp.544-551

Non-patent document 2: philip L. Alger, 'introduction mechanisms', Second Edition, April,1969

Disclosure of Invention

Problems to be solved by the invention

A stationary power conversion device using power semiconductor switching elements (hereinafter, referred to as "switching elements" in the present invention) can be roughly classified into a separately-excited current-type converter using switching elements such as thyristors which do not have a self-extinguishing function (hereinafter, referred to as "LCC converter") and a self-excited voltage-type converter using switching elements such as IGBTs which have a self-extinguishing function (hereinafter, referred to as "VSC converter").

In particular, in the case of the VSC converter, as the voltage of the switching element increases, the time rate of change of the coil voltage of the rotating electric machine increases, and as the switching characteristics improve, the PWM frequency increases to suppress the harmonic current, which increases the leakage current of the coil.

In particular, it is a bottleneck in the case of making an ac rotary electric machine provided on the premise of a commercial ac frequency power supply variable in speed.

The MMC converter is classified as a VSC converter equipped with PWM control. Unlike the conventional PWM converter, the MMC converter can suppress the amplitude of voltage ripple caused by PWM control to 1/N without using complicated wiring for a reactor and a transformer by connecting unit converters in series in N stages, thereby suppressing higher harmonic components of voltage applied to the ac rotary electric machine. By using the MMC converter, the coil insulation of the rotary electric machine can be used without being strengthened, and it is particularly preferable to change the speed of the ac rotary electric machine provided on the premise of a fixed frequency of the ac power supply system.

In addition, the MMC converter can improve usability by providing redundancy to the number of series connections of the unit converters and short-circuiting the output terminals of the failed unit converters. Therefore, the MMC converter is suitable for the case of variable speed of a large-capacity ac rotary electric machine requiring a plurality of unit converters.

Non-patent document 1 discloses a technique suitable for achieving this feature. Patent document 4 proposes that a variable-speed generator/motor apparatus can be realized by connecting a zcmcmc converter.

However, the above-mentioned document 2 does not disclose a problem and a solution that inevitably occur when an MMC converter is applied to change the speed of an ac rotary electric machine.

The first problem arises from the property of the MMC converter that the output current capacity is proportional to the frequency. This problem is that, since the current capacity is reduced in the low-frequency output region, the starting torque of the ac rotary electric machine, which is output torque in proportion to the current in principle, cannot be ensured. In particular, the synchronous machine is not suitable for starting the synchronous machine, and the synchronous machine occupies most of large-capacity rotary electric machines which are suitable for playing the features of the MMC converter. The problem is a general problem in the case of connection to an ac rotating electric machine regardless of the DSMMC converter, the DIMMC converter, and the zcmcmc converter, and the problem and the solution are not disclosed in

patent documents

1 and 4.

The second problem is a problem that occurs when a direct current is intentionally superimposed on a winding of a rotary electric machine.

Non-patent document 2 discloses p.356 that "imbalance of magnetic attraction force due to the meandering leakage flux based on the combination of the numbers of slots of the stator and rotor core of the induction machine also becomes a problem. ".

Further, when a direct current is intentionally superimposed as in the DIMMC converter or the zcmcmc converter, it is a minimum requirement to cancel a direct-current magnetomotive force due to a coil current inside the core slot. This problem is a general problem when a synchronous machine or an induction machine is used as an ac rotary electric machine.

On the other hand, patent document 4 proposes "if 3 equal parts of dc current are caused to flow through the 3-phase winding, the magnetic field generated by the zero-phase current becomes zero".

Non-patent document 2 describes 3 types of armature windings from p.76 to p.79. The winding of a single-layer coil is described in fig. 3.5, the winding of a 60-degree phase band of a 2-layer coil is described in fig. 3.6, and the winding of a 120-degree phase band of a 2-layer coil is described in fig. 3.7. The patent document 4 proposes that "if a 3-phase winding is supplied with 3 equal parts of dc current, the magnetomotive force in the slots is cancelled out, and the magnetic field generated by the zero-phase current is zero" is only a 120-degree phase band structure formed by the 2-layer coil shown in fig. 3.7. Hereinafter, 3 types of windings will be described.

In the case of a single-layer coil, the magnetomotive force cannot be cancelled in principle because the coil current in the slot is a single phase.

Fig. 21 shows an example of a 60-degree phase band in which the armature winding of a 2-pole machine is formed as a 2-layer coil accommodated in 18 slots.

Fig. 21 shows magnetomotive force distribution and magnetic field distribution when 3 equal parts of direct current are passed through each phase by star-connecting 3-phase windings of fig. 3.6 obtained by circumferentially spreading fig. 3.3 of non-patent document 2. In fig. 21, the solid line represents the upper layer coil of the 2-layer coil, and the broken line represents the lower layer coil.

Here, the magnetomotive force distribution generated by each phase winding when 3 equal parts of direct current IDC/3 were passed from the N terminal to the 3-phase (RST) terminal, and the magnetomotive force distribution and the magnetic field distribution obtained by summing up the 3-phase parts are shown. As shown in fig. 21, the dc current generates a magnetic field distribution close to a sine wave, and thus is not practical.

Next, fig. 7 shows an example in which a 120-degree phase band is formed by 2-layer coils in which armature windings of a 2-pole machine are accommodated in 18 slots.

Fig. 7 shows magnetomotive force distribution and magnetic field distribution when 3 equal parts of direct current flows through the windings of fig. 3.7 of non-patent document 2, in which the windings of fig. 3.7 are star-connected by changing the short-pitch winding (coil pitch 8/9) to the full-pitch winding, and 3-phase windings are connected in a star-like manner. In fig. 7, the solid line represents the upper layer coil of the 2-layer coil, and the broken line represents the lower layer coil.

Here, the magnetomotive force distribution generated by each phase winding when 3 equal parts of direct current IDC/3 were passed from the N terminal to the 3-phase (RST) terminal, and the magnetomotive force distribution and the magnetic field distribution obtained by 3-phase summation are shown. As shown in fig. 7, the in-groove magnetic potential caused by the dc current superposition section is cancelled out, and the contribution to the magnetic field distribution is zero.

In the above, when the zcmcmc converter and the ac rotary electric machine are connected to form the variable-speed generator/motor apparatus, it is a necessary condition for the ac rotary electric machine that "3 equal parts of dc current are superimposed on each phase of the armature winding of the 120-degree phase-band formed of the 2-layer coils".

However, when the speed of the installed ac rotary electric machine is changed, the winding factor and the harmonic component are prioritized in many cases, and the application example of the 120-degree phase band is not necessarily many. Therefore, the method of patent document 4 is limited in the case where the speed of the installed equipment can be changed.

On the other hand, even in the case of the armature winding of the 60-degree phase band constituted by the 2-layer coil, the in-slot magnetomotive force caused by the 3-divided direct-current superimposed current can be cancelled out by the method shown in fig. 4, and the contribution to the magnetic field distribution can be made zero.

In fig. 4, each magnetic pole generated by the 3-phase coil of fig. 21 is equally divided, and the direct currents 3 superimposed on the first group of 3-phase terminals (RP, SP, TP) and the second group of 3-phase terminals (RN, SN, TN) are equally divided, and the direct currents of the opposite polarities are superimposed on each other.

In this case, the magnetomotive force distribution generated by each phase winding, and the magnetomotive force distribution and the magnetic field distribution of the 3 phases in total are shown. As shown in fig. 4, the in-groove magnetic potential caused by the dc current superimposed portion can be cancelled out, and the contribution to the magnetic field distribution can be made zero. However, the zcmcmc converter has a problem that a direct current of opposite polarity cannot be superimposed.

The present invention has been made to solve the above problems and an object of the present invention is to provide a variable speed generator-motor apparatus and a variable speed generator-motor system using a large ac generator-motor.

Means for solving the problems

In order to achieve the above object, the present invention provides a variable speed generator-motor apparatus, in which an ac electromechanical armature winding is a 2-layer coil 60-degree phase band, divided into a positive side and a negative side, and connected to a neutral terminal as a star connection, the positive side terminal is connected to a first terminal of a DIMMC converter arm, the negative side terminal is connected to a second terminal of the DIMMC converter arm, and dc currents of the positive side and negative side windings are set to the same value of opposite polarities, and are divided into 3 equal parts for each phase, thereby canceling and stabilizing magnetomotive force due to a dc current component in a coil slot.

Alternatively, in order to achieve the above object, a variable speed generator/motor apparatus is provided in which an armature winding of an ac rotating electrical machine is formed into a 120-degree phase band of a 2-layer coil, and a direct current 3 is equally divided among arms of a zcmcmc converter, thereby canceling and stabilizing a magnetomotive force caused by a portion where direct currents overlap in coil slots.

Alternatively, to achieve the above object, the present invention provides a variable speed generator-motor apparatus, wherein an armature winding of a 4 × n-pole ac rotary electric machine is a 2-layer coil 60-degree phase band, 2-phase windings (2 × n) are equally divided into 2 phases in a positive electrode and a negative electrode and connected in series to the respective phases, 2 sets of 3-phase terminals are provided in a star-shaped connection in which m-paths are connected in parallel, n and m are natural numbers, the positive-side 3-phase terminal is connected to a first terminal of a DIMMC converter arm, a second terminal is connected to a positive-side terminal of a dc power supply apparatus, the negative-side 3-phase terminal is connected to a second terminal of the DIMMC converter arm, the first terminal is connected to a negative-side terminal of the dc power supply apparatus, the dc current values for the MMC converter arms are made to be the same, the positive-side and negative-side arms are made to be magnetomotive, the positive-side and negative-side arms are equally divided, stabilizing; meanwhile, the DIMMC converter can be bypassed. In particular, when the speed of an AC rotating electrical machine in which (2 x m) parallel star-shaped connections of (4 x n) poles are connected is variable by changing the coil end connections of the armature windings, the terminal voltage can be maintained before and after the change, and therefore, a variable speed generator-motor apparatus is provided which can continue the operation of an existing AC device without bypassing the inverter.

Alternatively, in order to achieve the above object, the present invention connects a synchronous machine with a damping winding to a DSMMC converter, a DIMMC converter, or a zcmcmc converter, short-circuits the excitation winding in resistance in a stopped state, starts the MMC converter with the arm current and frequency fixed at about 10% of their respective ratings, and starts an induction machine for an ac rotary electric machine.

Alternatively, in order to achieve the above object, the present invention temporarily stops the MMC converter when the rotational speed is accelerated to a frequency corresponding to the converter frequency, then changes the connection of the field winding from a resistance to the field converter, and restarts and accelerates the MMC converter with a current command proportional to the rotational speed. Thus, a variable speed generator-motor device capable of self-starting is provided.

Effects of the invention

According to the present invention, the speed of the ac rotary electric machine can be changed by changing only the coil end of the armature winding, on the premise that the ac rotary electric machine is operated at a fixed frequency based on the ac system. In particular, variable speed of an ac rotary electric machine in a wind power generation facility and a hydroelectric power generation facility can be realized quickly and effectively to suppress fluctuation of a power system due to expansion of use of regenerative energy in a solar power generation system, a wind power generation system, or the like.

Drawings

FIG. 1 is a circuit diagram showing a first embodiment of the present invention;

FIG. 2 is a circuit diagram showing a unit converter according to an embodiment of the present invention;

FIG. 3 is a circuit diagram showing another unit converter according to the embodiment of the present invention;

fig. 4 is a diagram showing an armature winding of an ac rotary electric machine according to a first embodiment of the present invention;

FIG. 5 is a control block diagram showing the first embodiment of the present invention;

FIG. 6 is a circuit diagram showing a second embodiment of the present invention;

fig. 7 is a diagram showing an armature winding of an ac rotary electric machine according to a second embodiment of the present invention;

FIG. 8 is a control block diagram showing a second embodiment of the present invention;

FIG. 9 is a circuit diagram showing a third embodiment of the present invention;

fig. 10 is a circuit diagram showing a dc power supply device according to a third embodiment of the present invention;

fig. 11 is a circuit diagram showing another dc power supply device according to a third embodiment of the present invention;

fig. 12 is a view showing an armature winding of an ac rotary electric machine according to a third embodiment of the present invention;

FIG. 13 is a control block diagram showing a third embodiment of the present invention;

FIG. 14 is an operation timing chart showing the third embodiment of the present invention;

FIG. 15 is a circuit diagram showing a fourth embodiment of the present invention;

fig. 16 is a circuit diagram showing a dc power supply device according to a fourth embodiment of the present invention;

fig. 17 is a view showing an armature winding of an ac rotary electric machine according to a fourth embodiment of the present invention;

FIG. 18 is a control block diagram showing a fourth embodiment of the present invention;

FIG. 19 is a control block diagram showing a fifth embodiment of the present invention;

FIG. 20 is an operation timing chart showing a fifth embodiment of the present invention;

fig. 21 is a diagram showing an armature winding of a conventional ac rotary electric machine (single star connection 60-degree phase belt);

fig. 22 is a diagram showing an armature winding of a conventional ac rotary electric machine (two-way star connection 60-degree phase belt);

fig. 23 is a diagram showing an armature winding of a conventional ac rotary electric machine (two-way star connection 120-degree phase belt).

Detailed Description

Hereinafter, embodiments of the variable speed generator/motor apparatus and the variable speed generator/motor system according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiment.

(first embodiment)

Fig. 1 is a circuit diagram showing a first embodiment of the present invention.

Reference numeral 101A denotes a dc power supply device, and an ac rotating electric machine 102A having 2 sets of star-shaped wires is provided with 3-phase terminals (RP, SP, TP) and 3-phase terminals (RN, SN, TN), and is grounded via a high resistance, by connecting neutral points of the 2 sets of star-shaped wires and leading to an N terminal. 6 arms (104RP, 104SP, 104TP, 104RN, 104SN, 104TN) having 2 terminals (a, b) are provided, the 2 terminals (a, b) are configured by N-stage series connection of output terminals (x, y) of the unit converter 103 of the MMC converter, the b terminal of the 3 arms (104RP, 104SP, 104TP) is star-connected to the first terminal (P) of the dc power supply device 101A, and the a terminal is connected to the 3-phase terminal (RP, SP, TP) of the ac rotary electric machine 102A. The a terminals of the remaining 3 arms (104RN, 104SN, 104TN) are star-connected to the second terminal (N) of the dc power supply device 101A, and the b terminals are connected to the 3-phase terminals (RN, SN, TN) of the ac rotary electric machine 102A.

Reference numeral 105A denotes a control device, which receives signals from a dc current transformer 106 for measuring output currents of 6 arms, a dc voltage transformer 107A for measuring line-to-line voltages of 3-phase terminals (RP, SP, TP), a dc voltage transformer 107B for measuring line-to-line voltages of 3-phase terminals (RN, SN, TN), and a phase detector 108 for measuring a rotation phase θ indicated by an electrical angle, performs control calculation, and outputs gate signals (GateP, GateN) to the unit converter 103. The

circuit breakers

109A and 109B are closed during normal use and open during maintenance. The phase detector 108 can estimate the rotational phase θ by vector operation from the line-to-line voltages from the

dc voltage transformers

107A and 107B and the current signal from the dc current transformer 106.

Patent document 5 discloses a vector operation method of an ac signal that changes at a rotational speed frequency, and a method of calculating a phase of an internal induced voltage corresponding to a rotational phase θ from a voltage signal and a current signal.

Fig. 2 is a circuit diagram showing the unit converter 103 according to the first embodiment. In the unit converter 103, the switching element 201 and the switching element 202 constituting the bidirectional chopper circuit are connected to a capacitor 203 as an energy storage element having a voltage source characteristic, and PWM control is performed by a gate signal for the switching

elements

201 and 202 input from an optical communication cable 204A connected to the control device 105A to the gate driver 207A via the optical-electrical conversion element 205A and the serial-parallel conversion circuit 206A, thereby adjusting an average voltage between the 2 terminals (x, y) between 0 and the capacitor voltage VC. On the other hand, the capacitor voltage VC returns the analog signal output from the dc voltage transformer 208 to the control device 105A through the analog-to-digital converter 209, the parallel-to-serial converter 210, and the electro-optical conversion element 211 via the optical communication cable 204A. With this configuration, the current flowing through the switching element is limited to either the switching element 201 or the switching element 202, and the loss can be minimized.

Fig. 3 is a circuit diagram showing another mode of the unit converter 103 according to the first embodiment. In the unit converter 103B, switching

elements

212, 213, 214, and 215 constituting a full bridge circuit are used instead of the bidirectional chopper circuit shown in fig. 2. According to this configuration, when the capacitor voltage is set to VC, the average voltage between the terminals (x, y) can be adjusted between-VC and + VC.

Fig. 4 shows an example of connection between the armature winding and the terminal of the ac rotary electric machine according to the first embodiment. For simplicity, a structure close to the minimum structure, i.e., an example of a 2-pole machine with the number of slots 18, is embodied. In addition, the salient pole synchronous machine is drawn for easy understanding of the relationship with the excitation, but may be a cylinder synchronous machine or an induction machine.

The following description will be given of the winding and terminal structure of fig. 4 that can be realized by the connection change of the coil end and the terminal lead-out from the winding and terminal structure shown in fig. 21.

In both fig. 21 and 4, the 60-degree phase band structure is formed by 2-layer coils, and the coil portion passing through the slot is not changed. In fig. 21 before modification, a coil for generating a magnetic field of positive and negative polarity is connected in series to the gap in a single star connection which is a normal 3-phase terminal (R, S, T). In fig. 4 after modification, 2 sets of 3-phase terminals (RP, SP, TP) and (RN, SN, TN) are provided.

As described above, the connection of the coil end of the armature winding is changed and the 3-terminal is additionally drawn. Since the number of turns of the 3-phase winding is reduced by half by the connection change, the line-to-line voltage is 1/2 before modification. Before and after the transformation, the current capacity of the armature coil is not changed. However, the manner of use of the current capacity changes.

Hereinafter, a case where a synchronous machine is used as the ac rotary electric machine will be described. The current frequency before modification is only the frequency of an alternating current system, and the effective value of the current is the square root of the square sum of the effective power component and the ineffective power component. The modified current is the square root of the sum of the squares of the effective value of the output frequency component of the power conversion device and the average value of the direct current. In principle, the phase voltages of the 2 sets of 3-phase terminals are in the same phase, and the effective values are also equal. When the signs of the alternating currents (IRP _ AC, ISP _ AC, ITP _ AC), (IRN _ AC, ISN _ AC, ITN _ AC) flowing through the 2 groups of windings are defined by fig. 1, the currents are in the reverse phase and have the same effective value. The ac current control is a power factor of 1. Here, the ac phase voltage of the power conversion device is VAC, the effective value of the current is IAC, the dc current is IDC, and the dc current is equally divided with respect to each phase winding 3. When the output voltage of the dc power supply device 101A is VDC, the relationship with the output capacity P is (P is 6 × VAC × IAC is VDC × IDC) when the loss of the ac rotating electric machine or the power conversion device is ignored. The ratio of (IDC/3) to IAC differs depending on the capacity of the capacitor 203 of the unit converter 103, the method of use in the event of a power failure, and whether the unit converter is shown in fig. 2 or fig. 3.

In general, when the capacity of the capacitor 203 is reduced, and the utilization rate of the capacitor voltage VC is reduced by suppressing the upper and lower limits of the PWM modulation rate of the unit converter in order to improve the usability (continuous operability) at the time of power supply abnormality, and the bidirectional chopper circuit of fig. 2 is used as the unit converter with importance placed on the efficiency of the power conversion device, the ratio of (IDC/3) is increased, and the equivalent power factor is reduced. When the ratio of (IDC/3) is designed to be high, it is assumed that (IDC/3)/IAC is 0.5. As a result, when the effective portion of the current capacity contributing to the output is IAC and the dc overlap portion (IDC/3) is the ineffective portion, the equivalent power factor is reduced to about 0.9. This value does not change in the manner of the MMC converter.

As a result, if the rated power factor of the synchronous machine before modification is 0.9 or less, the same effective power output can be ensured even after modification. In the case of using an inductor as an ac rotating electric machine, the power factor cannot be adjusted, so the modified effective power output is reduced to a value multiplied by the equivalent power factor of the MMC converter.

Fig. 5 is a control block diagram showing the control device 105A of the first embodiment.

501A is a phase voltage operator, which operates phase voltage signals by 2 groups of 3-phase line voltage detection signals. Reference numeral 502 denotes a speed calculator which calculates the rotational speed frequency ω from the current value of the rotational phase θ and the number Np of samples of the signal from the same phase in the previous cycle. Here, when the sample period is Δ t, ω is2 × pi/(Np × Δ t).

Reference numeral 503A denotes a moving average calculator which calculates the dc current IDC by moving averaging the total amount of the 3-phase ac currents (IRP, ISP, ITP) Np times. d-q converter 504P performs the operation of equation 1, and d-q converter 504N performs the operation of equation 2. However, here, the phase sequence is set to RST.

[ mathematical formula 1]

[ mathematical formula 2]

505A is a power operator, which uses an instantaneous symmetric coordinate method to calculate the effective power P and the ineffective power Q from the rotation phase signal, the phase voltage signal and the alternating current signal.

506A is an active power regulator, and 507A is an inactive power regulator, and outputs current commands ID and IQ, respectively, so that the calculated value P, Q coincides with command values P and Q. Reference numeral 508A denotes an ac current regulator, and performs control operation such that the measured value IDP coincides with one command value obtained by equally dividing the command value ID by 2, the measured value IDN coincides with a command value obtained by inverting the polarity of another command value obtained by equally dividing the command value ID by 2, and performs control operation such that the measured value IQP coincides with one command value obtained by equally dividing the command value IQ by 2, and the measured value IQN coincides with a command value obtained by inverting the polarity of another command value obtained by equally dividing the command value IQ by 2. 509A is a dc current regulator, and performs control operation such that a dc current command IDC obtained by dividing an output command value P by an output voltage VDC of the dc power supply coincides with a measurement operation value IDC.

In this embodiment, the degree of freedom of the current path is 5, 4 integration calculators are provided in the ac

current regulator

508A, and 1 integration calculator is provided in the dc current regulator 509A. Since the total of 5 integrating operators is equal to the current path degree of freedom 5, all the integrating operators can independently suppress the input deviation to zero. 510P and 510N are inverse d-q converters that perform the operation of equation 3.

[ mathematical formula 3]

511P is a dc voltage command correction calculator for the arms 104RP, 104SP, and 104TP, and 511N is a dc voltage command correction calculator for the arms 104RN, 104SN, and 104TN, and outputs output voltage commands VRP, VSP, VTP, VRN, VSN, and VTN for each arm.

From the above, when the phase voltages of the 3-phase terminals (RP, SP, TP) and the 3-phase terminals (RN, SN, TN) of ac rotary electric machine 102A are substantially equal to each other, and when the phase voltages are set to (VR, VS, VT), the output voltage commands to arm 104RP and arm 104RN are approximately:

VRP*＝+VR*+(1/2)×VDC

VRN*＝-VR*+(1/2)×VDC。

from these output voltage commands and the capacitor voltage VC of the unit converter 103, the gate commands GateP and GateN are output by the

PWM operators

512P and 512N.

(second embodiment)

Fig. 6 is a circuit diagram showing a second embodiment of the present invention.

Reference numeral 101A denotes a dc power supply device, and an ac rotary electric machine 102B having 1 set of star-shaped wirings is provided with a 3-phase terminal (R, S, T), and the neutral point of the star-shaped wirings is led to an N terminal and connected to a second terminal (N) of the dc power supply device 101A. Provided are 3 arms (604R, 604S, 604T) each having 2 terminals (a, B) and formed by connecting N stages of output terminals (x, y) of a unit converter 103 of an MMC converter in series, wherein the a terminal of the 3 arms is connected to a 3-phase terminal (R, S, T) of an ac rotary electric machine 102B, and the B terminal is star-connected to a first terminal (P) of a dc power supply device 101A.

Reference numeral 605A denotes a control device, which receives signals from the dc current transformer 106 for measuring the output current of the 3 arms, the dc voltage transformer 607 for measuring the line voltage of the 3-phase terminal (R, S, T), and the phase detector 108 for measuring the rotational phase θ indicated by the electrical angle, performs control calculation, and outputs a Gate signal Gate to the unit converter 103. The circuit breaker 609 is closed during normal use and open during maintenance. The phase detector 108 can estimate the rotational phase θ by vector operation from the line-to-line voltage from the dc voltage transformer 607 and the current signal from the dc current transformer 106. The unit converter 103 is implemented in fig. 2 or 3.

Fig. 7 shows an example of connection between the armature winding and the terminal of the ac rotary electric machine according to the second embodiment. For simplicity, the structure of the example of a 2-pole machine embodying the slot number 18 is close to the minimum structure. In addition, the salient pole synchronous machine is drawn for easy understanding of the relationship with the excitation, but may be a cylinder synchronous machine or an induction machine.

The winding of fig. 7 is a 120-degree phase band structure of 2-layer coils. Is a normal single star connection leading out a 3-phase terminal (R, S, T).

Hereinafter, a case where the ac rotary electric machine is a synchronous machine will be described. The current before modification is the frequency of an alternating current system, and the effective value of the current is the square root of the square sum of the effective power component and the ineffective power component. The transformed current is the output frequency and the direct current of the power conversion device. The alternating currents (IR, IS, IT) are controlled to a power factor of 1. Here, the ac phase voltage and the current of the power conversion device have effective values VAC and IAC, the superimposed dc current is IDC, and the dc current is equally divided into phases with respect to the phase windings 3. When the output voltage of the dc power supply device 101A is VDC, the relationship with the output capacity P is (P is 3 × VAC × IAC is VDC × IDC) when the loss of the ac rotating electric machine or the power conversion device is ignored. The ratio of (IDC/3) to IAC is the same as in fig. 1, and the description thereof will be omitted to avoid redundancy.

If the rated power factor of the machine is below 0.9 before modification, the same effective power output can be ensured after modification. In the case of using an inductor as an ac rotating electric machine, the power factor cannot be adjusted, so the modified effective power output is reduced to a value multiplied by the equivalent power factor of the MMC converter.

Fig. 8 is a control block diagram showing a control device 605A according to the second embodiment.

Reference numeral 501B denotes a phase voltage calculator which calculates a phase voltage signal from the line voltage detection signal. Reference numeral 502 denotes a speed calculator, and 503A denotes a moving average calculator, which calculates a direct current IDC by moving averaging the total amount of 3-phase alternating currents (IR, IS, IT) Np times. d-q converter 504C performs the operation of equation 4. The phase sequence indicates the case of RST.

[ mathematical formula 4]

505B is a power operator, which uses the phase voltage signal and the alternating current signal to calculate the effective power P and the ineffective power Q by using an instantaneous symmetric coordinate method.

506B is an active power regulator, and 507B is an inactive power regulator, which respectively outputs current commands ID and IQ such that the calculated value P, Q coincides with command values P and Q. Reference numeral 508B denotes an ac current regulator, which performs control operation so that the measured values ID and IQ match the command values ID and IQ. 509B is a dc current regulator, and performs control operation so that a dc current command IDC obtained by dividing an output command value P by an output voltage VDC of the dc power supply coincides with a measurement operation value IDC.

In this example, since the degree of freedom of the current path is 3, and the total of 2 integration calculators of the ac

current regulator

508B and 1 integration calculator of the dc current regulator 509B is 3, the degree of freedom is equal to the degree of freedom of the current path, it is possible to suppress the input deviation of all the integration calculators to zero independently. 510C is an inverse d-q converter, which performs the operation of equation 3.

511C is a dc voltage command correction arithmetic unit for the

arms

604R, 604S, 604T, and outputs output voltage commands VR, VS, VT for the respective arms.

From above, when the phase voltages at the 3-phase terminal (R, S, T) of the ac rotary electric machine 102B are set to (VRG, VSG, VTG), the output voltage command to the arm 104R is as follows:

VR*＝+VRG*+(1/2)×VDC。

from these output voltage commands and the capacitor voltage VC of the unit converter 103, the Gate command Gate is output by the PWM operator 512C.

(third embodiment)

Fig. 9 is a circuit diagram showing a third embodiment of the present invention. Here, the ac rotary electric machine 902A is a synchronous machine provided with a damping winding.

An ac rotary electric machine 902A having 2-group star connections is provided with 3-phase terminals (RP, SP, TP) and 3-phase terminals (RN, SN, TN), and neutral points of the 2-group star connections are connected to be drawn to the N terminal and grounded via a high resistance.

The dc power supply device 901 performs power conversion between an ac system side terminal (A, B, C) and a dc side terminal (P, N). The ac system side terminal (A, B, C) is connected from the ac system 903 via the circuit breaker 904.

The dc power supply 901 has 3 sets of ac terminals (UP, VP, WP) (UM, VM, WM) (UX, VX, WX) in addition thereto. The ac terminals (UP, VP, WP) are connected to 3-phase terminals (RP, SP, TP) of the ac rotary electric machine 902A via a breaker 905P and a circuit breaker 906. The 3-phase terminals (RN, SN, TN) of the ac rotary electric machine 902A are connected from the ac terminals (UM, VM, WM) via a breaker 905N. Further, the 3-phase terminals (RP, SP, TP) and the 3-phase terminals (RN, SN, TN) are connected by breakers 907A and 907B. The ac terminals (UX, VX, WX) are branched to the excitation power converter 911 via the built-in power supply system 920, the excitation chopper 909, and the excitation transformer 910. The field winding 908 is connected to a chopper 914 connected to a resistor 913 and a chopper 912 connected to a power converter 911 for excitation by switching.

The ac system 903 is connected to ac terminals (UP, VP, WP) and (UM, VM, WM) via a primary charging transformer 915, a primary charging interrupter 916, a current limiting resistor 917, and a primary charging connection interrupter 918. In addition, a bypass breaker 919 is provided for the current limiting resistance 917.

Fig. 10 is a circuit diagram showing an embodiment of a dc power supply 901A to which the DIMMC converter disclosed in patent document 2 is applied.

The transformer 1001 connects an ac system side terminal (A, B, C) to the primary winding, and the secondary and tertiary windings are connected in a two-way star connection and are connected to ac terminals (UP, VP, WP) and (UM, VM, WM), respectively. The ac terminals (Up, Vp, and Wp) of the transformer 1001 are connected to the a terminals of 3 2 terminal arms (1004Up, 1004Vp, and 1004Wp) that connect the unit converters 103 in series, and the b terminals are star-connected to the dc terminals (P). On the other hand, the ac terminals (Um, Vm, Wm) are connected to the b terminals of 3 2 terminal arms (1004Um, 1004Vm, 1004Wm) that are connected in series to the unit converter 103, and the a terminals are star-connected to the dc terminal (N). Transformer 1001 is provided with a quadruple winding connected in a delta configuration, and has both a function of supplying power to an internal power supply and an exciting circuit and a function of suppressing a third harmonic.

Fig. 11 is a circuit diagram showing another embodiment of a dc power supply 901B to which the DSMMC converter disclosed in patent document 1 is applied.

The same reference numerals as in fig. 10 denote the same components, and their description will be omitted to avoid redundancy.

An alternating current system side terminal (A, B, C) of the transformer 1002 is connected to the primary winding, and secondary winding terminals (Ut, Vt, Wt) of the delta connection are connected to neutral points (Ux, Vx, Wx) of the 3-group 3-terminal reactor 1003. The 3-terminal reactor 1003 has terminals (Up, Vp, and Wp) connected to terminals a of 3 2-terminal arms (1004Up, 1004Vp, and 1004Wp) that connect the unit converters 103 in series, and has terminals b connected to the dc terminals (P) in a star configuration. On the other hand, the terminals (Um, Vm, Wm) of the 3-terminal reactor 1003 are connected to the b-terminals of 3 2-terminal arms (1004Um, 1004Vm, 1004Wm) connected in series to the unit converter 103, and the a-terminal is star-connected to the dc terminal (N). The power is supplied from the secondary winding of the transformer 1002 to the internal power supply or the exciting circuit via the ac terminals (UX, VX, WX).

Hereinafter, a procedure of charging the capacitor 203 of the unit inverter 103 of the dc power supply device 901 will be described with reference to the configuration of fig. 9. During the charging period, the

breakers

905P and 905N maintain an open state.

When the first-time charging interrupter 916 and the first-time charging connection interrupter 918 are closed with the bypass interrupter 919 kept open, the charging of the capacitor 203 of the unit converter 103 is started while suppressing the inrush current by the current limiting resistor 917. Next, the bypass breaker 919 is closed to accelerate charging. After the charging by diode rectification based on the ac terminal voltage of the primary charging transformer 915 is completed, the primary charging connection breaker 918 is opened and the breaker 904 is closed to charge the

transformer

1001 or 1002 of the dc power supply device 901, and then the capacitor voltage is boosted and charged to a desired voltage by PWM control of the unit converter 103.

Next, the dc power supply 901 supplies power to the 6-arm (104RP, 104SP, 104TP, 104RN, 104SN, 104TN) unit inverters 103 on the ac rotary electric machine 902A side, and the capacitors 203 of the respective unit inverters are charged by PWM control.

After the charging is completed in this way, the ac rotary electric machine 902A is kept stopped, and only the unit inverter 103 on the dc power supply device 901 side is operated, and thus the operation as the reactive power adjusting device is possible. When the french pump turbine is directly connected to the ac rotary electric machine 902A, the phase sequence is inverted in the power generation direction and the pumping direction, but the switching can be performed only by the control of the inverter, and a phase inversion breaker is not necessary.

According to the present embodiment, since all the unit converters are already charged, the unit converters can be started quickly during operation in either the power generation or motoring direction.

Fig. 12 shows an example of connection between an armature winding and a terminal of an ac rotary electric machine according to a third embodiment. For simplicity, a 4-pole machine with a slot number 36 close to the minimum configuration is shown. In addition, in order to show the relation with the excitation, a salient pole synchronous machine is drawn, but a cylindrical excitation synchronous machine or an induction machine may be used.

The winding and terminal structure of fig. 12 can be realized by only changing the coil end portion from the winding and terminal structure shown in fig. 22. Fig. 22 shows a two-way star-connected 4-pole machine, which is a 60-degree phase-band structure of a typical 2-layer coil. In the example of fig. 22, the total of 6 windings of 3 windings on the positive electrode side and 3 windings on the negative electrode side are provided for each phase. The star-shaped connection is connected in parallel with two ways by an inter-pole crossover line.

On the other hand, in fig. 12, the windings of the first group of 3-phase terminals (RP, SP, TP) are connected in series with both positive electrodes, and the total number of windings is 6. The other winding of the 3-phase terminals (RN, SN, TN) has two cathodes connected in series for a total of 6 windings.

According to the embodiment of fig. 12, since the number of turns is not changed before and after the modification, the rated voltage can be maintained. Therefore, the flag 906 or the like can be used. In addition, when the embodiment of fig. 11 is used as a dc power supply device, the transformer 1002 can be used as it is because the secondary terminal voltage of the transformer 1002 is not changed before and after the modification.

In the configuration of fig. 9, the operation can be performed by bypassing the MMC converter. Specifically, the ac rotary electric machine 902A can be operated as a 3-phase two-way star-connected generator by closing the

circuit breakers

905P and 905N, the circuit breaker 906, and the circuit breakers 907A and 907B. Under the condition of being directly connected with the French water pump turbine, the phase sequence is connected with the power generation direction, so that the MMC converter can be bypassed for power generation application.

Fig. 13 is a control block diagram showing a control device 905 according to the third embodiment. Since the same reference numerals as those in fig. 5 denote the same components, the description thereof will be omitted to avoid redundancy.

Reference numeral 1301 denotes a command switch (SW1) which switches commands to a fixed start frequency ω S and a fixed rotation speed frequency ω. Reference numeral 1302 denotes a current command generator which outputs a current command ID proportional to the rotational speed frequency ω. Reference numeral 1303 denotes a current command generator, and outputs ID ═ 0. Reference numeral 1304 denotes a command switch (SW2) which selectively switches the active power regulator 506A, the current command generator 1302, and the current command generator 1303, and outputs a current command ID.

Reference numeral 1305 denotes a command switch (SW3) for selectively switching the active power command P and the active power measurement value P. Reference numeral 1306 denotes a power calculator, and the output of the line-to-line voltage effective value VGM of the ac rotating electric machine 902A is added to the power calculator 505. Reference numeral 1307 denotes a voltage command generator, which is a voltage command VGM generator proportional to the rotation speed frequency ω, 1308 denotes a voltage regulator of the ac rotary

electric machine

902A, 1309 denotes a current command generator, and outputs IQ ═ 0. Reference numeral 1310 denotes a command switch (SW4) which selects the switching voltage regulator 1308, the current command generator 1309, and the reactive power regulator 507A and outputs a current command IQ.

As described above, fig. 14 shows a method for starting the ac generator/motor apparatus according to the embodiment of fig. 9 and 13.

First, a starting method in the motor mode is explained.

In fig. 14, at time Tm1, the capacitor of the unit converter 103 has been charged in advance, the circuit breaker 904 is closed, and the

circuit breakers

905P, 905N, 907A, and 907B are kept in an open state.

The interrupter CBE2 is closed (ON), the CBE3 is Open (OFF), the command switch SW1 is set to the fixed side of the fixed speed command ω S, and the command switch SW2 is set to the command side ID of the speed ratio (ID ═ k ω). The command switch SW3 is set to the active power measurement value P side, and the command switch SW4 is set to IQ ═ 0.

In the above state, the MMC converter is started at time Tm2 (MMC control _ on), and ac rotating electric machine 902A starts in the damped winding based induction mode. When the rotation speed reaches the set value ω S at time Tm3, the MMC converter is temporarily stopped (MMC control _ off), and CBE3 is closed, thereby being connected to the power converter 911 for excitation. Next, CBE2 is opened at time Tm4, separating resistor 913. At the same time, the command switch SW1 is switched to the rotational speed frequency ω (rotational speed ω), and the command switch SW4 is switched to the output side (AVR) of the voltage regulator 1308. Thus, the ID command outputs a command value proportional to the speed, and the IQ command also outputs a command value proportional to the speed. At the same time, excitation control is started. When the MMC converter control is started at time Tm5 (MMC control _ on) while this state is maintained, acceleration is started with the synchronous machine torque. When the rotation speed ω enters the variable speed operation range, the output of the command switch SW2 is temporarily switched to ID ═ 0 at the time Tm6, the command switch SW2 is set to the output side (APR) of the active power regulator at the time Tm7, the command switch SW3 is set to the command P side, the command switch SW4 is set to the output side (AQR) of the inactive power regulator, and the normal variable speed motor mode operation is performed.

As described above, according to the present embodiment, the self-starting in the motor mode can be performed without depending on the starting device.

Next, a starting method in the power generation mode will be described.

In fig. 14, at Tg1, the capacitor 203 of the unit converter 103 has been charged in advance, the circuit breaker 904 remains closed, and the

circuit breakers

905P, 905N, 907A, 907B remain open.

The circuit breaker CBE2 is open, CBE3 is closed, the command switch SW1 is not used (set to one because it is not fixed), and the command switch SW2 is set to the ID ═ 0 side. The command switch SW3 is set to the side of the active power measurement P and the command switch SW4 is set to the side of the voltage regulator output.

In the power generation mode, the rotational speed of the prime mover directly connected to the ac rotary electric machine 902A is controlled by a governor of the prime mover, and the prime mover is started and accelerated by the drive torque of the prime mover.

In the above state, at Tg1, the vehicle is accelerated while being adjusted by the speed governor on the prime mover side. The ac rotary electric machine 902A is kept in a no-load state. After the rotational speed is accelerated to the variable speed range, the rotational speed command for the governor is held fixed at Tg 2. At this time, since the phase signal θ is a rotational phase, the voltage induced at the terminal of the ac rotating electric machine 902A is synchronized with the phase of the voltage command. At Tg3, the instruction switch SW4 is toggle set to the inactive power regulator side while the MMC control is started. Then, the command switch SW2 is switched to the active power regulator output side at Tg4, and the command switch SW3 is switched to the active power command P ″, so that the normal variable speed generator mode operation is performed.

(fourth embodiment)

Fig. 15 is a circuit diagram showing a fourth embodiment of the present invention. The same reference numerals as those in fig. 6 and 9 denote the same components. The description thereof is omitted to avoid redundancy. Here, ac rotating electric machine 1502A is a synchronous machine provided with a damping winding.

In ac rotary electric machine 1502A including 2 sets of star-type connections, 3-phase terminals (R1, S1, T1) and 3-phase terminals (R2, S2, T2) are provided, and neutral points of the 2 sets of star-type connections are connected to the N terminal and are connected to second terminal (N) of dc power supply device 1501. 6 arms (1504R1, 1504S1, 1504T1, 1504R2, 1504S2, 1504T2) each having 2 terminals (a, b) are provided, the 2 terminals (a, b) are formed by connecting N stages of output terminals (x, y) of the unit converters 103 of the MMC converter in series, the b terminal of the 3 arms (1504R1, 1504S1, 1504T1) is star-connected to the first terminal (P) of the dc power supply device 1501, and the a terminal is connected to the 3-phase terminal (R1, S1, T1) of the ac rotary electric machine 1502A. The b terminals of the remaining 3 arms (1504R2, 1504S2, 1504T2) are star-connected to the first terminal (P) of the dc power supply device 1501, and the a terminals are connected to the 3-phase terminals (R2, S2, T2) of the ac rotary electric machine 1502A.

Reference numeral 1605 denotes a control device, which receives signals from 6 dc current transformers 106, a dc voltage transformer 107C for measuring the line-to-line voltage of the 3-phase terminals (R1, S1, and T1), a dc voltage transformer 107D for measuring the line-to-line voltage of the 3-phase terminals (R2, S2, and T2), and a phase detector 108 for measuring the rotational phase θ indicated by the electrical angle, performs control calculation, and outputs Gate signals (Gate1 and Gate 2) to the unit converter 103. The circuit breaker 1505 is closed during normal use and open during maintenance. The circuit breaker 1507 is opened in normal operation and closed in bypass operation.

The dc power supply device 1501 performs power conversion between an ac system side terminal (A, B, C) and a dc side terminal (P, N). The ac system side terminal (A, B, C) is connected to the ac system 903 via the circuit breaker 904.

The dc power supply device 1501 includes 2 sets of ac terminals (U, V, W) (UX, VX, WX) in addition. The ac terminal (U, V, W) is branched at a breaker 1507 through a breaker 1505 and a breaker 1506, and then connected to 2-group 3-phase terminals (R1, S1, and T1) and (R2, S2, and T2) of the ac rotary electric machine. The ac terminals (UX, VX, WX) are branched to the excitation power converter 911 via the built-in power supply system 920, the excitation chopper 909, and the excitation transformer 910. The excitation winding 908 is connected to a chopper 914 connected to a resistor 913 and a chopper 912 connected to an excitation power converter 911.

The ac system 903 is connected to an ac terminal (U, V, W) via a primary charging transformer 915, a primary charging interrupter 916, a current limiting resistor 917, and a primary charging connection interrupter 1518. In addition, a bypass breaker 919 is provided for the current limiting resistance 917.

Fig. 16 is a circuit diagram showing an embodiment of a dc power supply device 1501 to which the zcmcmc converter disclosed in patent document 3 is applied.

An AC system side terminal (A, B, C) of the transformer 1601 is connected to the primary winding, and the secondary and tertiary windings are connected in a zigzag manner to an AC terminal (U, V, W). An ac terminal (U, V, W) of the transformer 1601 is connected to the a terminals of 3 2 terminal arms (1602U, 1602V, 1602W) in which the unit converters 103 are connected in series, and the b terminal is star-connected to the dc terminal (P). On the other hand, the neutral point of the zigzag connection is connected to the DC terminal (N). The transformer 1601 is provided with a quadruple winding connected in a delta configuration, and has a function of supplying power to an internal power supply and an exciting circuit and a function of suppressing a third harmonic.

Fig. 17 shows an example of connection between an armature winding and a terminal of an ac rotary electric machine according to the fourth embodiment. For simplicity, a 4-pole machine with a slot number 36 close to the minimum configuration is shown. In addition, although the salient pole synchronous machine is drawn to show the relation with the excitation, the salient pole synchronous machine may be a cylindrical excitation synchronous machine or an induction machine.

The winding and terminal structure of fig. 17 can be realized by changing only the coil end portion from the winding and terminal structure shown in fig. 23. Fig. 23 shows a two-way star-connected 4-pole machine, which is a 120-degree phase band structure of a typical 2-layer coil. In the example of fig. 23, each phase is 6 windings. The star-shaped connection is connected in parallel with two ways by an inter-pole crossover line.

On the other hand, in fig. 17, the two-way star connection is divided into 2 groups and independent terminals are drawn out, and the windings of the first group of 3-phase terminals (R1, S1, T1) and the 2 nd group of 3-phase terminals (R2, S2, T2) are wound for a total of 6 times as in fig. 23.

According to the embodiment of fig. 17, since the number of turns is not changed before and after the modification, the rated voltage can be maintained. Therefore, the breaker 1506 and the like can be used.

In the configuration of fig. 15, the operation can be performed by bypassing the MMC converter. Specifically, the ac rotary electric machine 1502A can be used as a 3-phase two-way star-connected generator by closing the circuit breaker 1505, the circuit breaker 1506, and the circuit breaker 1507. Under the condition of being directly connected with a French water pump turbine, the phase sequence is connected with the power generation direction, and the MMC converter can be bypassed for power generation.

According to the embodiment of fig. 17, when the current capacity of the ac rotary electric machine 1502A is increased and star connection is performed in parallel, the current of each arm can be reduced by dividing the parallel winding equally and drawing the terminals in segments. This reduces the number of switching elements connected in parallel in the unit converter 103, simplifies the structure, and improves reliability.

Fig. 18 is a control block diagram showing a control device 1605 according to the fourth embodiment. Since the same reference numerals as those in fig. 5 and 8 denote the same components, the description thereof will be omitted to avoid redundancy.

1801A is a phase voltage operator, which calculates a phase voltage signal from the line voltage detection signal. Reference numeral 502 denotes a speed calculator,

reference numerals

503A and 503B denote moving average calculators, and the dc currents IDC1 and IDC2 are calculated by moving averages Np times of the total amount of 2 sets of 3-phase ac currents (IR1, IS1, and IT1) (IR2, IS2, and IT 2).

d-q converters

1804A and 1804B perform the operation of equation 4 and output (ID1, IQ1) (ID2, IQ2), respectively. The phase sequence indicates the case of RST.

1806 is a power operator, which uses the phase voltage signal and the ac current signal to calculate the effective power P and the ineffective power Q by an instantaneous symmetric coordinate method.

506B is an active power regulator, and 507B is an inactive power regulator, which output current commands ID and IQ, respectively, so that the calculated value P, Q coincides with the active power command P and the inactive power command Q. Reference numeral 508B denotes an ac current regulator, and control calculations are performed so that the command values obtained by equally dividing the current command ID by 2 coincide with the measurement calculation values ID1 and IQ1, respectively, and control calculations are performed so that the command values obtained by equally dividing the current command IQ by 2 coincide with the measurement calculation values ID2 and IQ2, respectively. 1809A and 1809B are dc current regulators, the dc current regulator 1809A performs control calculation so that a command value obtained by dividing the dc current command IDC obtained by dividing the output command value P by the output voltage command VDC of the dc power supply by 2 is equal to the measurement calculation value IDC1, and the dc current regulator 1809B performs control calculation so that a command value obtained by dividing the dc current command IDC obtained by dividing the output command value P by the output voltage command VDC of the dc power supply by 2 is equal to the measurement calculation value IDC 2.

In the case of this embodiment, the degree of freedom of the current path is 6, and the total of 4 integration calculators for the ac

current regulator

508B and 2 integration calculators for the dc current regulator is 6, and is equal to the degree of freedom of the current path, so that all the integration calculator input deviations can be independently suppressed to zero. 1810C and 1810D are inverse D-q converters that perform the operation of equation 3.

1811A is a dc voltage command correction arithmetic unit for the arms 1504R1, 1504S1, 1504T1, and outputs VR1, VS1, and VT1, and 1811B is a dc voltage command correction arithmetic unit for the arms 1504R2, 1504S2, 1504T2, and outputs VR2, VS2, and VT 2.

From the above, when the phase voltages of the 3-phase terminals (R1, S1, T1) (R2, S2, T2) of the 2 groups of parallel windings of ac rotary electric machine 1502A are equal and (VR, VS, VT), the output voltage command VR1 for arm 1504R1 and the output voltage command VR2 for 1504R2 are as follows:

VR1*＝+VR*+(1/2)×VDC

VR2*＝+VR*+(1/2)×VDC。

gate commands Gate1 and Gate2 are output from these output voltage commands and the capacitor voltage VC of the unit converter 103 through

PWM operators

1812A and 1812B.

(fifth embodiment)

Fig. 19 is a control block diagram showing a control device 905 of the fifth embodiment. Since the same reference numerals as those in fig. 13 denote the same members, the description thereof will be omitted to avoid redundancy.

In this embodiment, the synchronous machine 902A with damping windings of the system of the present invention is directly connected to a pump or a reversible pump turbine, and a sealing valve is provided on the discharge side of the pump or the reversible pump turbine. Reference numeral 1901 denotes a rotational speed command generator which outputs a speed ω p at which an input Pp at the time of establishing a hydraulic pressure and a motor input Pm at the time of acceleration determined by the characteristics of the variable speed power generation electric system coincide, based on a full head signal Hp. When the fluctuation range of the total head is small, the command generator for outputting a fixed value can be simplified. Reference numeral 1902 denotes a rotational speed regulator which regulates the current command ID so that the deviation of the rotational speed command ω p from the rotational speed frequency ω becomes zero. Reference numeral 1903 denotes a command switch (SW5) which switches the current command ID on the basis of the rotational speed command ω p and the rotational speed frequency ω as determination conditions.

In view of the above, fig. 20 shows a method for starting up the ac generator-motor system in the embodiment of fig. 9 and 19. The same reference numerals as in fig. 14 denote the same elements, and a description thereof will be omitted to avoid redundancy.

When the MMC converter is started at time Tm2 (MMC control _ on), ac rotary electric machine 902A starts in the damping winding-based induction mode, and active power Pm rises from 0. At time Tm3, when the rotation speed ω becomes equal to the set value ω S, the MMC converter is temporarily stopped (MMC control _ off), and the active power Pm returns to 0. The CBE3 is closed and connected to the excitation power converter 911. Next, CBE2 is opened at time Tm4, causing resistor 913 to separate. At the same time, the command switch SW1 is switched to the rotation speed frequency ω, and the command switch SW4 is switched to the output side (AVR) of the voltage regulator 1308. Thus, the ID command outputs a command value proportional to the speed, and the IQ command also outputs a command value proportional to the speed. At the same time, excitation control (excitation control _ on) is started. When the MMC converter control is started at time Tm5 (MMC control _ on) while this state is maintained, acceleration is started with the synchronous machine torque. Since the voltage and the current during this period are both proportional to the rotation speed ω, the motor input Pm increases in proportion to the square of the rotation speed ω. On the other hand, the input Pp at the time of the hydraulic pressure establishment is increased by the rotation speed ω, but the change is small compared to the motor input Pm, and therefore there is always the rotation speed ω at which both coincide. This value varies depending on the full head range or the specific speed of the turbomachine, and empirically converges between 50% and 90% if the rotational speed at the nominal input is 100%. This value is calculated by the rotational speed command generator 1901 and output as a rotational speed command ω p. When the rotation speed ω is accelerated to the command value ω p, the command switch SW4 is switched to the output (AQR) of the reactive power regulator 507A at the same time as the current command ID output from the command switch SW5 is switched to the output (ASR) of the rotation speed regulator 1902 at the time Tm 8. Since the acceleration is stopped at the time Tm8, the motor input Pm temporarily drops, but when the seal valve is opened at the time Tm9 to establish the hydraulic pressure (seal valve _ on), the motor input Pm rises again in response to a sharp rise in the pump or pump turbine input Pp. In order to suppress the variation of the motor input Pm during this period, the timing of opening the sealing valve is adjusted so that the time difference Δ Tp between the time Tm9 and the time Tm8 is as short as possible, and the accuracy of the rotational speed command generator 1901 is increased to reduce Δ Pp. After the rotation speed fluctuation at the time of the water pressure establishment is fixed by the rotation speed regulator 1902, the current command ID is switched to the output (APR) of the active power regulator by the command switch SW5 at the time Tm10, the command switch SW3 is switched to the command P side, and the normal variable speed motor mode operation is performed.

According to the present embodiment, since the starting torque can be secured, the water surface depressing device is not required, and the water pump or the pump turbine can be accelerated from the water charging state from the stop time, so that the starting time can be shortened. In addition, since the acceleration period can be operated at the upper limit of the output current capacity of the unit inverter 103, the acceleration time can be shortened. Further, since the variation in the motor input at the time of the water pressure establishment can be suppressed to the minimum, the load adjustment of the ac system and the like which are necessary in the conventional water raiser are not required, and the effect of flexible operation is obtained.

In the above embodiments, the 3-phase ac rotary electric machine has been described as an example, but it is needless to say that the embodiments of the present invention can be extended to an N-phase ac rotary electric machine. In the above embodiments, the overlapping winding is described as an example of the winding method, but it is needless to say that the embodiments of the present invention can be extended to the wave winding.

Description of the symbols

101A, 901A, 901B, 1501: a direct current power supply device;

102A, 102B, 902A, 1502A: an AC rotating electrical machine;

903: an alternating current system;

904. 906, 912, 914, 1506: a breaker;

1001. 1002, 1601: a transformer;

1003: a 3-terminal reactor;

920: an in-house power supply system;

908: an excitation winding;

909: a circuit breaker for excitation;

910: a transformer for excitation;

911: a power converter for excitation;

913: a resistor;

917: a current limiting resistor;

915: a transformer for primary charging;

916: a breaker for primary charging;

918. 1518: a breaker for primary charging connection;

919: a bypass breaker;

109A, 109B, 609, 905P, 905N, 907A, 907B, 1505, 1507: a circuit breaker;

104RP, 104SP, 104TP, 104RN, 104SN, 104TN, 604R, 604S, 604T, 1004UP, 1004VP, 1004WP, 1004UM, 1004VM, 1004WM, 1504R1, 1504S1, 1504T1, 1504R2, 1504S2, 1504T2, 1602U, 1602V, 1602W: an arm;

106: a direct current transformer;

107A, 107B, 107C, 107D, 208, 607, 507A, 507B: a direct current voltage transformer;

103: a unit converter;

201. 202, 212, 213, 214, 215: a switching element;

105A, 605A, 905, 1605: a control device;

203: a capacitor;

204A, 204B: an optical communication cable;

205A, 205B: an optical-electrical conversion element;

206A: a serial-parallel conversion circuit;

207A: a gate driver;

209: an analog-to-digital converter;

210: a parallel-to-serial converter;

211: an electro-optical conversion element;

501A, 501B, 1801A: a phase voltage operator;

502: a speed arithmetic unit;

503A, 503B: a moving average calculator;

504P, 504N, 504C, 1804A, 1804B: a d-q converter;

505A, 505B, 1306, 1806: a power calculator;

506A, 506B: an active power regulator;

507A, 507B: an invalid power regulator;

508A, 508B: an alternating current regulator;

509A, 509B, 1809A, 1809B: a DC current regulator;

510P, 510N, 510C, 1810D: an inverse d-q converter;

511P, 511N, 511C, 1811A, 1811B: a DC voltage command correction arithmetic unit;

512P, 512N, 512C, 1812A, 1812B: a PWM operator;

1301. 1304, 1305, 1310, 1903: an instruction switcher;

1302. 1303, 1309: a current command generator;

1307: a voltage command generator;

1308: a voltage regulator;

1901: a rotational speed instruction generator;

1902: a rotational speed regulator.

Claims

1. A variable-speed power-generating electric device comprising a power converter connected to a DC power supply and a 3-phase AC rotating electric machine connected to an AC side of the power converter,

the power converter comprises 62 terminal arms, wherein the 2 terminal arms are obtained by connecting k 2-terminal unit converters capable of outputting any voltage through an energy storage element with voltage source characteristics in series, wherein k is a natural number more than 1,

the AC rotary electric machine comprises an armature winding with 2-layer coils and 60-degree phase bands, the armature winding is divided into a first electrode side and a second electrode side, a neutral point terminal is connected to form a two-way star connection, the two-way star connection is led out through 2 groups of 3-phase terminals,

the 3-phase terminals on the first pole side of the armature winding are connected to first terminals of 3 2-terminal arms of the power converter, respectively, second terminals of the 3 2-terminal arms are star-connected to a first terminal of the DC power supply,

the 3-phase terminal on the second pole side of the armature winding is connected to the second terminals of the remaining 3 2-terminal arms of the power converter, respectively, the first terminals of the 3 2-terminal arms are star-connected to the second terminal of the dc power supply,

the variable speed power generation electric device is provided with a means for dividing a direct current 3 of the direct current power supply into equal parts and sequentially passing the 3 2-terminal arms connected to the second terminal of the direct current power supply, the 3-phase terminal on the second electrode side of the armature winding, the 3-phase terminal on the first electrode side of the armature winding, and the 3 2-terminal arms connected to the first terminal of the direct current power supply for each phase.

2. A variable-speed power-generating electric device comprising a power converter connected to a DC power supply and a 3-phase AC rotating electric machine of (4 x n) poles connected to an AC side of the power converter, wherein n is a natural number of 1 or more,

the AC rotary electric machine comprises an armature winding with 2 layers of coils and 60-degree phase bands, wherein the first pole side and the second pole side of the armature winding are divided into windings with (2 x n) poles connected in series for each phase and are connected in parallel by m paths to obtain a star connection, a neutral point terminal of the star connection is connected, the opposite side of the winding is led out through 2 groups of 3-phase terminals, wherein m is a natural number more than 1,

the variable speed power generation electric device includes a unit that divides a direct current of the direct current power supply by 3 equally and passes the 3 2-terminal arms connected to a second terminal of the direct current power supply, the 3-phase terminal on a second electrode side of the armature winding, the 3-phase terminal on a first electrode side of the armature winding, and the 3 2-terminal arms connected to a first terminal of the direct current power supply in this order.

3. A variable speed generating electric system comprising a power converter connected to a DC power source and a synchronous machine with a damping winding connected to an AC side of the power converter,

the power converter comprises 2 terminal arms, wherein the 2 terminal arms are obtained by connecting k 2-terminal unit converters capable of outputting any voltage through an energy storage element with voltage source characteristics in series, wherein k is a natural number more than 1,

the variable-speed power generation electric system is provided with:

a first control unit that adjusts a frequency and an amplitude of a current supplied from the power converter to the synchronous machine to fixed values;

a second control unit that synchronizes a frequency of a current supplied from the power converter to the synchronous machine with a rotation speed of the synchronous machine and adjusts an amplitude of the current to a value proportional to the frequency; and

a switching unit for short-circuiting the field winding of the synchronous machine by a resistor when the first control unit is used and connecting the field winding of the synchronous machine to an excitation device when the second control unit is used,

and when the synchronous machine is started from a stop state, the first control unit is used, and if the frequency reaches a set value, the second control unit is switched to.

4. The variable speed generating electrical system of claim 3,

a water pump or a reversible pump turbine is directly connected to the synchronous machine with the damping winding, a sealing valve is arranged on the discharge side,

the variable-speed power generation electric system is provided with:

a third control unit generating a rotational speed command according to a head signal of the water pump or the reversible pump turbine and adjusting the rotational speed to the rotational speed command,

when acceleration to the rotational speed command is detected by the second control means, the sealing valve is opened and the control is switched to the third control means.

5. A variable-speed power-generating electric device comprising a power converter connected to a DC power supply and an N-phase AC rotating electric machine connected to an AC side of the power converter, N being a natural number of 3 or more,

the power converter comprises (2 x N) 2 terminal arms, wherein the 2 terminal arms are obtained by connecting k 2-terminal unit converters capable of outputting any voltage through an energy storage element with voltage source characteristics in series, wherein k is a natural number more than 1,

the AC rotary electric machine comprises an armature winding with 2 layers of coils and a (180/N) degree phase belt, wherein neutral point terminals are connected to the first pole side and the second pole side of the armature winding as two-way star-shaped connection lines and are led out through 2 groups of N-phase terminals,

the N-phase terminal on the first electrode side of the armature winding is connected to first terminals of N2-terminal arms of the power converter, second terminals of the N2-terminal arms are star-connected to a first terminal of the DC power supply, the N-phase terminal on the second electrode side of the armature winding is connected to second terminals of the remaining N2-terminal arms of the power converter, and the first terminals of the N2-terminal arms are star-connected to a second terminal of the DC power supply,

the variable speed power generation electric device is provided with a means for dividing a direct current N of the direct current power supply into equal parts and sequentially passing the N2 terminal arms connected to a second terminal of the direct current power supply, the N-phase terminal on a second electrode side of the armature winding, the N-phase terminal on a first electrode side of the armature winding, and the N2 terminal arms connected to a first terminal of the direct current power supply for each phase.

6. A variable-speed power-generating electric device comprising a power converter connected to a DC power supply and a (4 x N) -pole N-phase AC rotating electric machine connected to an AC side of the power converter, wherein N is a natural number of 1 or more and N is a natural number of 3 or more,

the AC rotary electric machine comprises an armature winding with 2 layers of coils and a (180/N) degree phase belt, wherein the first pole side and the second pole side of the armature winding are divided into windings with (2 x N) poles connected in series for each phase and are connected in parallel by m paths to obtain a star connection, a neutral point terminal of the star connection is connected, the opposite side of the winding is led out through 2 groups of N-phase terminals, wherein m is a natural number more than 1,

the N-phase terminals on the first pole side of the armature winding are connected to first terminals of N2-terminal arms of the power converter, respectively, second terminals of the N2-terminal arms are star-connected to a first terminal of the DC power supply,

the N-phase terminals on the second pole side of the armature winding are connected to second terminals of the remaining N2-terminal arms of the power converter, respectively, first terminals of the N2-terminal arms are star-connected to second terminals of the DC power supply,